Check the end switches
Check that the two middle shafts (the ones that cross the head) ain't touching the sides or the front of the um2 structure.
By end switches - Do you mean the limit switches? If yes, I checked them. They seem to work fine. The two middle shafts also do not touch structure of the UM2.
Can you move the head around by hand?
You can unclip the head assembly from the black guides that are connected to the belts.
One removed you can individually check to see which one might be stuck.
It might a cable touching the gears?
Can you move the head around by hand?
You can unclip the head assembly from the black guides that are connected to the belts.
One removed you can individually check to see which one might be stuck.
Yes the head is easily movable. When tried to move it to home base. Its easily moves back from any position.
Checked the cables, none are touching the gears.
Have you checked to make sure the pulleys are tight?
Yes, checked the pulleys. They seem tight. Compared them to the other UM2 I have. Seem to be the same on how tight they are.Have you checked to make sure the pulleys are tight?
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What was the solution to this?
I have had my UMO+ for less then a month and it started doing this exact same thing.
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Please post a video of your issue @bsilverwood also check if when the machine is off the head moves ok or has friction. Also check that all gear/shafts are perfectly aligned and thatthe puleys on the shafts that connects to the x/y motors with the short belts ain't touching the bearings directly, they should have at least a very small, tinny amount of air (in my experience).
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I am getting the exact same thing as the OP and at approximately the same spot. I mean this is a carbon copy of the issue.
Manually moving the head forward, I do feel more resistance, and this is at the same place it appears that the head stops and makes noise.
I have also confirmed the alignment is good, and no wires appear to be interfering with anything.
Can tou make a photo of all the pulleys/belt maybe it's just a pulley that you installedon the oposite direction. Just thinking outloud.
Also just in case check the belts run perfectly parallel to each shaft.
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I'll get a picture posted ASAP.
On a side note, Eliminating the motor from the equation, just sliding front to back it sticks about every couple inches.
It's like I can feel it sticking, then it releases. then it sticks and releases.
Curious - If the sliding blocks are not completely tight (with the print head shafts) could this possibly cause some contention?
I recall that the y print head shaft was more of a pain to put in.
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I'm getting really frustrated here...
The motor is not connected (to cause any resistance) and the y axis is still sticking. I have tried a little oil on the rods. Physically inspected them short of removing them out of the damn machine.
Nothing is rubbing on anything (belts on the side of the unit, belts on wires, pulleys on wires.)
It will take a gorilla on Redbull to loosen any of the pulleys.
The print head just won't move smoothly on the y axis. It moves and then sticks (move freely where i can use 1 hand to move it, then I need two hands and force to "un-stick" it.
Could is be a bent rod? The box wasn't damaged wit hshipping and this just started to happen (after I JUST fixed my feeder problem).
I have had this printer for about 3 weeks and it's about to become firewood as I have only had 2 VERY SMALL prints successful.
On the photo posted the pulley it's almost inside the wood panel, that can't happen. Can you check that? You need some air on that point, even just half half mm.
There is actually a gap here. Not a lot though (like you mentioned you need only 1mm which is about all i have on it).
I don't think it has anything to do with the motor pulleys, but rather the other 4 that drives the head on the y axis.
This week I'm going to take the whole top side off and re-do the bars, pulleys, stops, and belts. I had all kinds of feeder issues till I did this exact same thing and meticulously go through the install guide and triple checking everything.
Maybe someday I will actually get this thing working...
Just start loosening things.
I'd start with all the Y axis endcaps. That can cause significant friction.
Having the belts too tight can also hurt.
Having things crooked at the print head also hurts - in other words if the 2 rods aren't perpendicular.
Loosen all the pulley screws. It might be that a belt skipped a tooth. To fix you loosen all 4 long belt pulleys for that axis and square it up and re-tighten.
Just start loosening things.
I'd start with all the Y axis endcaps. That can cause significant friction.
Having the belts too tight can also hurt.
Having things crooked at the print head also hurts - in other words if the 2 rods aren't perpendicular.
Loosen all the pulley screws. It might be that a belt skipped a tooth. To fix you loosen all 4 long belt pulleys for that axis and square it up and re-tighten.
This was the direction I was thinking. I figure while I am at it I will line the pulley screws up too for easier calibration in the future.
You mentioned about the belts being too tight. I noticed that the long belts for the XY axises are very tight in general. Should there be a little give on them?
On the UMO my belts are quite loose. There's a video of Eric (one of the founders) plucking it like a guitar string. That's the best and most helful of how tight it should be. The pitch should be below or almost below human pitch hearing but you need to be experienced with knowing the pitch of 20Hz so it's best to watch the video. Someone should say something like:
Push head all the way to the side, hang 100gram weight on band. Deflection should be 3mm at center. Something like that.
Really you want them pretty tight but not so tight that you feel an increase in friction when you push the head around. If they are too loose you get "play" aka "backlash" (look it up in wikipedia) and you get things like infill not touching the walls of your part properly and strange effects where walls stick out near holes but not in other places and more strangeness.
Thank you everyone on your advice and recommendations.
I have all the XY bars, pulleys, belts apart ATM and tonight I will be putting it all back together.
One thing to note. Reading the build instructions and other conversations, I am curious to how my XY motors are mounted and the location of the pulleys on the shafts of the motors. One of the two motor shafts (with the pulley attached) appears to stick out through the wooden frame by about 1-2mm. Now, according to the build notes, the pulleys need to be right up against the end of the motor shaft. To me, this would then put the belt of the pulley VERY close to the side of the unit and could be a point of rubbing and resistance. Am I on the right track here? I was thinking of putting washers to space it out where the end of the motor shaft/pulley is flush with the outside wall of the unit. Another option is to just move the pulley back on the shaft closer to the motor where it appears to line up more similar to that of the other axis motor.
Neotko - I see in the picture you posted a pink guide that ensures that the belts and pulleys are parallel to each other. Is that something you printed off?
Since my printer is currently in parts ATM I am going to try to create something similar to use.
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neotko 1,417
Check the end switches
Check that the two middle shafts (the ones that cross the head) ain't touching the sides or the front of the um2 structure.
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